diff --git a/python/ngen_cal/src/ngen/cal/calibration_cathment.py b/python/ngen_cal/src/ngen/cal/calibration_cathment.py
index d68a1556..f15067bb 100644
--- a/python/ngen_cal/src/ngen/cal/calibration_cathment.py
+++ b/python/ngen_cal/src/ngen/cal/calibration_cathment.py
@@ -70,7 +70,7 @@ def __init__(self, nexus: Nexus, start_time: str, end_time: str, fabric: "GeoSer
         #If no `main_output_variable`, default to Q_OUT
         self._output_var = output_var
         #use the nwis location to get observation data
-        obs = self.outflow._hydro_location.get_data(start_time, end_time)
+        obs = self._outflow._hydro_location.get_data(start_time, end_time)
         #make sure data is hourly
         self._observed = obs.set_index('value_time')['value'].resample('1H').nearest()
         self._observed.rename('obs_flow', inplace=True)
@@ -142,4 +142,4 @@ def restart(self) -> int:
         except FileNotFoundError:
             pass
         return restart_iteration
-        
\ No newline at end of file
+